won 1992 Formula One driving championship with record 9 victories and 14 poles; quit Grand Prix circuit to race Indy cars in 1993; 1st rookie to win IndyCar title; 3rd driver to win IndyCar and F1 titles; returned to F1 after 1994 IndyCar season and won '94 Australian Grand Prix; left F1 again on May 23, 1995 with 31 wins and 32 poles in 15 years.